How to simulate seismic conditions with non-uniform excitation in Opensees？

[cexuhan]

Hi All,

According to my knowledge, the uniform excitation can be achieved in Opensees by calling the "UniformExcitation" sentence. But if I wanna simulate the earthquake cases with non-uniform excitation, that is, considering that the ground motion excitation of the earthquake at different bearing positions is different, is there any feasible way to simulate it in Opensees?

Thanks a lot for any possible help.

Xu

[mhscott]

Yes, search online for OpenSees multiple support excitation.

[cexuhan]

Yes, search online for OpenSees multiple support excitation.

Thanks for your reply. Best wishes.

[sonshitsu]

Hi All,

According to my knowledge, the uniform excitation can be achieved in Opensees by calling the "UniformExcitation" sentence. But if I wanna simulate the earthquake cases with non-uniform excitation, that is, considering that the ground motion excitation of the earthquake at different bearing positions is different, is there any feasible way to simulate it in Opensees?

Thanks a lot for any possible help.

Xu

Thank you.

[fatpanda]

Hi All,

According to my knowledge, the uniform excitation can be achieved in Opensees by calling the "UniformExcitation" sentence. But if I wanna simulate the earthquake cases with non-uniform excitation, that is, considering that the ground motion excitation of the earthquake at different bearing positions is different, is there any feasible way to simulate it in Opensees?

Thanks a lot for any possible help.

Xu

Yes, you're absolutely right about the use of "UniformExcitation" in OpenSees for simulating uniform earthquake ground motions. When it comes to simulating non-uniform earthquake excitations, where the ground motion varies at different support locations, OpenSees does offer ways to handle this more complex scenario.

Non-uniform excitations in an earthquake simulation are important to consider, especially for large structures or those on irregular terrain, where different parts of the structure may experience different motions during an earthquake.

To simulate non-uniform excitation in OpenSees, you would typically use multiple "LoadPattern" elements, each with its own ground motion record. This approach allows you to assign different ground motion records to different supports or sections of your model, representing the varying effects of the earthquake at those points.

Here's a simplified breakdown of the steps:

Define Multiple Load Patterns: Create separate LoadPattern elements for each unique ground motion you want to simulate.

1. For each LoadPattern, apply a ground motion using commands like "PathTimeSeries" and "PathSeries" to define the time history of the ground motion. The ground motion data can be actual recorded data or generated data that fits your earthquake scenario.

2. You can then assign these load patterns to different nodes or elements of your structural model. This assignment is where you simulate the non-uniform aspect of the earthquake - different parts of your structure will be subjected to different ground motions.

3. Configure your analysis to consider all these load patterns. This setup might require a more complex analysis configuration, as you're dealing with multiple, potentially interacting, ground motions.

4. Perform the analysis, and OpenSees will compute the response of your structure to these non-uniform excitations.

Remember, when setting up, it's crucial to ensure that the ground motion records and their assignments to different parts of the model accurately represent the earthquake scenario you are trying to simulate. Additionally, the complexity of non-uniform excitation analysis means that it's often more computationally demanding, so be prepared for longer run times and possibly higher resource requirements.